Cooling air inlet arrangement

ABSTRACT

A portable air compressor unit ( 10 ) having a housing ( 22 ) with a rear end ( 30 ) and front end ( 26 ). The housing ( 22 ) includes a rear louver ( 66 ) near the rear end ( 30 ), an exhaust outlet ( 74 ) near the front end ( 26 ) and a mid louver ( 70 ) between the rear and front end. A rear cooler set ( 82 ) and rear fan ( 106 ) are disposed within the housing between the rear louver and mid louver. The fan ( 106 ) draws cooling air into the housing through rear louver ( 66 ) and through the rear cooler set ( 82 ). A front fan ( 122 ) and front cooler set ( 130 ) are disposed within the housing ( 22 ) between the mid louver ( 70 ) and exhaust outlet ( 74 ).

This Patent Application claims the benefit of the earlier filing date of provisional patent application No. 60/259,989 filed Jan. 5, 2001.

FIELD OF THE INVENTION

This invention relates to air compressors, and more particularly to cooling systems for air compressors.

BACKGROUND OF THE INVENTION

To ensure the reliability of an air compressor in all environments, it is critical that an adequate supply of cool ambient air is properly routed through the compressor assembly and into key areas of the compressor. The operating requirements of the compressor and the engine are directly related to how well heat exchangers transfer heat from the compressor components to the ambient air. The unit design and layout must ensure that a sufficient amount of cool ambient air is available for all the heat exchangers, batteries, instrument panels, electronic controls, intakes to the compressor and engine, and other components. However, inlets that allow ambient air to enter the compressor housing also allow noise to leave the compressor housing. There is a trade off between cooling air and compressor noise, and manufacturer's must consider Environmental Protection Agency (EPA) and European Community (EC) noise requirements when designing air compressor units.

The need for ambient air is especially important for air compressor units operating in warm climates. Two common designs for air compressor units are a cold box design, and a hot box design. The difference between the cold box design and the hot box design is generally the order in which air passes over the heat exchangers, compressor and engine. The hot box is desirable in cold climates because the air flow is warmed while first passing through heat exchangers before passing over the compressor and the engine. The cold box is desirable in warm climates because the air flow first passes over the compressor and the engine and then passes through the heat exchangers. In both of these designs, the emissions and noise standards must be achieved while simultaneously maintaining proper compressor thermal operating conditions.

Therefore, it is advantageous to have an air compressor unit design that increases the ambient air intake to cool critical parts of the air compressor unit, while reducing the amount of noise released into the environment and maintaining a normal discharge temperature. It is also desirable to have an air compressor unit that possesses benefits from both a cold box design and a hot box design.

SUMMARY OF THE INVENTION

The present invention utilizes a two fan design with one fan in the rearward portion of the compressor housing, and a second fan in the forward portion of the housing. The housing preferably has rear louvers near the back of the housing and mid louvers near the intermediate section of the housing. These louvers have noise reducing baffles and are strategically located in the housing to accommodate the needs for cool air and directing the air to specific parts, while reducing the amount of noise emitted by the machine. The invention locates cool air inlets in certain locations to direct cool air across critical components. Cool ambient air is drawn through baffled louvers primarily by a hydraulic powered rear fan, and secondarily by the front fan.

A combination of a cold box design and a hot box design is utilized for the present invention. The cooling air flows through beat exchangers both before and after passing over the compressor and engine. The air that enters through the rear louvers passes through the rear cooler set, which includes several heat exchangers. These heat exchangers preferably include a fuel cooler, a hydraulic cooler, an air end oil cooler, an intercooler, and an aftercooler. The coolers transfer heat to the air and the temperature of the air increases after passing through the coolers. The air then flows past the compressor and draws some excess heat from the compressor before mixing with the additional air.

The front fan pulls supplemental cool air through baffled inlets near the door and mid-sections that mixes with the exhaust air of the previously mentioned coolers. The combined air then preferably passes over the engine and through another set of coolers that includes a radiator and a charge-air cooler. The radiator controls the operating temperature of the engine. The charge-air cooler controls the temperature of the turbo charged air entering the engine. The invention provides adequate ambient air to properly cool the compressor assembly while maintaining a normal compressor discharge temperature. In addition, the invention also meets current engine emission standards and complies with EPA and EC noise requirements.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an air compressor unit according to the preferred embodiment of the present invention;

FIG. 2 is a side view illustrating the left side of the air compressor unit shown in FIG. 1;

FIG. 3 is a side view illustrating the right side of the air compressor unit shown in FIG. 1;

FIG. 4 is a top cut-away view of the air compressor unit shown in FIG. 1.

Before the embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

FIG. 1 illustrates a portable air compressor unit 10 that compresses air to pressures above normal atmospheric pressures. The compressor unit 10 includes a frame 14, wheels 18 supporting the frame 14, and a housing 22 supported by the frame 14. The housing 22 has a front end 26 and a rear end 30 disposed at opposite ends of the housing 22. The housing 22 includes a base 34, a roof 38, a left portion 42, and a right portion 46 that extend between the front end 26 and the rear end 30. The compressor unit 10 also has a tongue 50 that may interconnect to a vehicle and facilitate transporting the portable air compressor unit 10.

The frame 14 supports the housing 22 and the internal components of the air compressor unit 10 disposed within the housing 22. In the illustrated embodiment, the housing 22 is a substantially rectangular box, but the housing may be any shape that substantially encloses the components of the compressor unit 10. The internal components of the air compressor unit 10 are described in more detail below, and may include compressors, engines, pumps, motors, heat exchangers, coolers, fans, controllers, and other related parts. The compressor unit 10 requires adequate ambient air flow through the housing 22 to properly cool the internal components within the housing 22.

The housing 22 includes multiple apertures with baffled louvers that permit cooling ambient air to enter the housing 22 and cool the internal components of the compressor unit 10. The left portion 42 includes a rear aperture 54 disposed near the rear end 30, and a mid aperture 58 disposed between the rear end 30 and the front end 26. The apertures 54, 58 are not limited to the side portions 62, and could also be located in the roof 38, base 34 or rear end 30. A rear louver 66 is disposed in the rear aperture 54 near the rear end 30, and a mid louver 70 is disposed in the mid aperture 58 between the rear end 30 and front end 26.

FIG. 1 also illustrates an exhaust outlet 74 disposed in the roof 38 near the front end 26. Air flow enters the housing 22 through the louvers 66, 70 and flows through the housing 22 in a generally forward direction from the rear end 30 toward the front end 26. The air flow exits the housing 22 through the exhaust outlet 74 near the front end 26.

FIG. 2 illustrates the left portion 42 of the housing 22, and shows the rear louver 66 and the mid louver 70. FIG. 3 illustrates the right portion 46 of the housing 22 and also shows the rear aperture 54 disposed near the rear end 30, and the mid aperture 58 disposed between the rear end 30 and front end 26. In the right portion 46, the rear louver 66 is disposed in the rear aperture 54, and the mid louver 70 is disposed in the mid aperture 58. In the illustrated embodiment, the rear louver 66 of the left portion 42 is opposite the rear louver 66 of the right portion 46, and the mid louver 70 of the left portion 42 is opposite the mid louver 70 of the right portion 46. The night portion 46 includes multiple mid louvers 70 and the left portion 42 includes one mid louver 70. The actual number of mid louvers 70 may vary slightly as long as the louvers 70 permit adequate cooling ambient air to enter the housing 22.

The compressor unit 10 is relatively loud, and noise may exit the housing 22 through the louvers 66, 70. Noise reduction is a concern for air compressors, and the present invention helps reduce the amount of noise emitted by the air compressor unit 10. The louvers 66, 70 includes baffles 78 to reduce the amount of noise emitted from the compressor unit 10. Additionally, the louvers 66, 70 are strategically located along the housing 22 in relation to internal components of the compressor unit 10 to maximize air intake into the housing 22 while minimizing the noise emitted from the housing 22.

FIG. 4 illustrates the internal components of the air compressor unit 10 within the housing 22, and the air flow through the housing 22. The air flow is described in more detail below. As shown in FIG. 4, the rear louvers 66 are disposed in the right portion 46 and left portion 42 near the rear end 30. Alternatively, the rear louvers 66 could be disposed in the rear end 30. Mid louvers 70 are disposed in the right portion 46 and left portion 42 between the rear end 30 and front end 26. The exhaust outlet 74 is disposed in the roof 38 near the front end 26. For the purpose of description, a rearward direction is generally from the front end 26 toward the rear end 30, and a forward direction is generally from the rear end 30 toward the front end 26.

The compressor unit 10 includes a rear cooler set 82 mounted near the rear end 30 forward of the rear louvers 66. The rear cooler set 82 includes multiple heat exchangers, such as a fuel cooler 86, a hydraulic cooler 90, an airend oil cooler 94, an intercooler 98, and an aftercooler 102. In the illustrated embodiment, one side of the rear cooler set 82 has the fuel cooler 86 on the top near the roof 38, the airend oil cooler 94 on the bottom near the base 34, and the hydraulic cooler 90 between the fuel cooler 86 and the airend oil cooler 94. The other side of the rear cooler set 82 has the intercooler 98 disposed above the aftercooler 102.

The fuel cooler 86 reduces the temperature of fuel for the compressor unit 10, and helps the air compressor unit 10 fulfill engine emission requirements. The hydraulic cooler 90 maintains the operating temperature of hydraulic fluid within the air compressor unit 10. The airend oil cooler 94 controls the temperature of the lubricating oil for the air compressor unit 10. The intercooler 98 and aftercooler 102 control the temperature of air compressed by the air compressor unit 10.

A rear fan 106 is mounted immediately forward of the rear cooler set 82, and is driven by a motor 110. In the illustrated embodiment, the motor 110 is hydraulic and is powered by the flow of hydraulic fluid, but any other suitable motor may be used. The rear fan 106 draws cool ambient air into the housing 22 through the rear louvers 66, and draws air through the rear cooler set 82. The rear fan 106 also pushes air forward through the housing 22.

The air compressor unit 10 includes an engine 114 and a compressor 118 disposed forward of the rear fan 106. The engine 114 powers the compressor 118 which compresses air. In the illustrated embodiment, the engine 114 is a diesel engine 114 and the compressor 118 is a two stage rotary compressor, but other engine and compressor designs may be used with this invention. Air flow past the compressor 118 and engine 114 helps cool the compressor 118 and engine 114. The mid louvers 70 are disposed near the engine 114 and compressor 118 to permit additional cooling air to enter the housing 22.

A front fan 122 is mounted forward of the engine 114. In the illustrated embodiment, the front fan 122 is larger than the rear fan 106, and generates a greater air flow than the rear fan 106. The mid louvers 70 are disposed between the rear fan 106 and the front fan 122, and the front fan 122 draws cooling ambient air into the housing 22 through the mid louvers 70. The engine 114 drives the front fan 122, and the engine 114 may also drive a hydraulic pump 126, which creates a hydraulic flow and powers the motor 110 and the rear fan 106

A front cooler set 130 is mounted near the front end 26 forward of the front fan 122. The front fan 122 generates air flow through the front cooler set 130. In the illustrated embodiment, the front cooler set 130 includes multiple heat exchangers, such as a radiator 134 and a charge-air cooler 138. The radiator 134 controls the operating temperature of the engine 114, and the charge-air cooler 138 controls the temperature of turbo charged air that enters the engine 114.

The exhaust outlet 74 is disposed forward the front cooler set 130, between the front cooler set 130 and the front end 26. The air flow through the housing 22 exits the housing 22 through the exhaust outlet 74. In the illustrated embodiment, the exhaust outlet 74 is an aperture in the roof 38. Alternatively, the exhaust outlet 74 could have baffled louvers or a mechanized louver system, or the exhaust outlet 74 could be disposed in the left portion 42, right portion 46, base 34, or front end 26.

In FIG. 4, arrows A, B, C, D, E and F illustrate the air flow through the housing 22. The air flow generally enters the housing 22 through rear louvers 66 and mid louvers 70, and exits the housing 22 through the exhaust outlet 74. As mentioned above, the air compressor unit 10 requires cooling ambient air flow through the housing 22 to cool the components of the air compressor unit 10. As the air cools the components, the temperature of the air increases. The rear cooler set 82 and front cooler set 130 include heat exchangers that reduce the temperature of the substance within the heat exchangers by transferring heat from the substance to the air flowing through the heat exchangers. Therefore, the temperature of the air increases after passing through the heat exchangers.

The ability of the air to cool the components is directly related to the temperature differential between the components and the air. The greater the temperature differential, the greater the cooling capacity of the air flow. The louvers 66, 70 and internal components of the air compressor unit 10 are positioned to maximize the cooling capacity of air flow through the housing 22, and minimize the noise emitted by the air compressor unit 10.

Primary air flow A enters the housing 22 through the rear louvers 66 in the left portion 42 and right portion 46. The rear cooler set 82 is disposed between the rear louvers 66 and the rear fan 106, and the rear fan draws air flow B through the rear cooler set 82. The rear cooler set 82 transfers heat from the various heat exchangers 86, 90, 94, 98, 102 to the air flow B, and increases the temperature of air flow B as it passes through the rear cooler set 82. The rear fan 106 then forces air flow C forward and past the compressor 118. Air flow C helps cool the compressor 118, and the temperature of air flow C generally increases after flowing past the compressor 118.

As described above, the housing 22 includes mid louvers 70 that are disposed intermediate the ends 26, 30, forward of the rear fan 106, and rearward of the front fan 122. Secondary air flow D enters the housing 22 through the mid louvers 70. Air flow D is generally cool ambient air, similar to air flow A, and the temperature of air flow D is generally lower than the temperature of air flow C. Air flow D mixes with air flow C into a combined air flow E to lower the air temperature and increase the cooling capacity of the air. The combined air flow E generally has a lower temperature and a greater cooling capacity than air flow C.

The front fan 122 draws the secondary air flow D into the housing 22, and draws the combined air flow E forward past the engine 114 to help cool the engine 114. The front cooler set 130 is disposed forward of the front fan 122, and the front fan 122 forces air flow F through the front cooler set 130. The front cooler set 130 transfers heat from the heat exchangers 134, 138 to the air flow F, and increases the temperature of air flow F as it passes through the front cooler set 130. After air flow F passes through the front cooler set 130, air flow G exits the housing 22 through the exhaust outlet 74.

As mentioned above, the front fan 122 driven by the engine 114 is larger than the rear fan 106 driven by the motor 110, such that the air flow F through the front cooler set 130 is greater than the air flow B through the rear cooler set 82. The greater air flow generated by the front fan 122 increases the cooling capacity of the air flow through the housing 22. This embodiment ensures that proper air flow is generated in the middle portions of the housing 22.

The louvers 66, 70 of the present invention are strategically located to provide adequate air flow for cooling while restricting the noise emitted from the air compressor unit 10. The primary air flow A generally increases in temperature after air flow B passes through the rear cooler set 82 and air flow C passes over the compressor 118. The mid louvers 70 are located near the engine 114 to allow the secondary air flow D to enter the housing 22 and cool the engine 114. The secondary air flow D is generally cooler than air flow C when they mix into combined air flow E. The temperature of combined air flow E is generally lower than the temperature of air flow C, so additional heat can be transferred to combined air flow F as it passes through the front cooler set 130.

The dual fan design of the air compressor unit 10 generates the proper air flow to draw enough air into the housing 22 and cool the compressor unit 10. Additionally, the strategically located louvers 66, 70 with baffles 78 limit the amount of noise emitted from the air compressor unit 10. The air flow through the housing 22 increases the reliability of the air compressor unit 10 in a wide range of operating conditions and environments. 

1. An air compressor unit comprising: a base; a housing supported by the base, the housing including: a first inlet in the housing near a first end of the housing; an outlet in the housing near a second end of the housing opposite the first end; and a second inlet in the housing disposed between the first inlet and the outlet; a first heat exchanger assembly disposed within the housing between the first inlet and second inlet; a first fan disposed within the housing between the first inlet and second inlet that generates an air flow in the housing; an engine and a compressor disposed within the housing near the second inlet; a second heat exchanger assembly disposed within the housing between the second inlet and the outlet; and a second fan disposed within the housing between the second inlet and the outlet that generates an air flow in the housing.
 2. The air compressor unit of claim 1, wherein the first heat exchanger assembly is disposed between the first inlet and the first fan.
 3. The air compressor unit of claim 1, wherein the second fan is disposed between the second inlet and the second heat exchanger assembly.
 4. The air compressor unit of claim 1, wherein the second fan is larger than the first fan, and the air flow past the second heat exchanger assembly is greater than the air flow past the first heat exchanger assembly.
 5. The air compressor unit of claim 1, wherein the first heat exchanger assembly includes a fuel cooler that reduces the temperature of fuel for the engine.
 6. The air compressor unit of claim 1, wherein the first heat exchanger assembly includes: a hydraulic cooler that reduces the temperature of hydraulic fluid within the air compressor unit; an airend oil cooler that reduces the temperature of lubricating oil for the air compressor unit; an intercooler that reduces the temperature of compressed air in the air compressor unit; and an aftercooler that reduces the temperature of compressed air discharged by the air compressor unit.
 7. The air compressor unit of claim 1, wherein the second heat exchanger assembly includes a charge-air cooler that reduces the temperature of turbo charged air that enters the engine.
 8. The air compressor unit of claim 1, wherein the second heat exchanger assembly includes a radiator that reduces the temperature of coolant in engine.
 9. The air compressor unit of claim 1, wherein the first inlet and second inlet have baffled louvers.
 10. An air compressor unit comprising: a base; a housing supported by the base, and having a rear end and a front end disposed at opposite ends of the compressor unit, and a rear aperture disposed near the rear end that permits air to enter the housing; a first heat exchanger assembly disposed within the housing forward of the rear aperture; a first fan disposed within the housing forward of the first heat exchanger that draws air flow into the housing through the rear aperture and past the first heat exchanger; a compressor disposed within the housing forward of the first fan; an engine disposed within the housing forward of the first fan that drives the compressor; a mid aperture in the housing forward of the rear fan that permits air to enter the housing; a second fan disposed within the housing forward of the mid aperture that draws air flow into the housing through the mid aperture; a second heat exchanger assembly disposed forward of the second fan, and the second fan forces air flow past the second heat exchanger assembly; and an outlet in the housing disposed forward of the second heat exchanger near the front end that permits air to exit the housing.
 11. The air compressor unit of claim 10, wherein the second fan is larger than the first fan, and the air flow past the second heat exchanger assembly is greater than the air flow past the first heat exchanger assembly.
 12. The air compressor unit of claim 10, wherein the first heat exchanger assembly includes a fuel cooler that reduces the temperature of fuel for the engine.
 13. The air compressor unit of claim 10, wherein the first heat exchanger assembly includes: a hydraulic cooler that reduces the temperature of hydraulic fluid within the air compressor unit; an airend oil cooler that reduces the temperature of lubricating oil for the air compressor unit; an intercooler that reduces the temperature of compressed air in the air compressor unit; and an aftercooler that reduces the temperature of compressed air discharged by the air compressor unit.
 14. The air compressor unit of claim 10, wherein the second heat exchanger assembly includes a charge-air cooler that reduces the temperature of turbo charged air that enters the engine.
 15. The air compressor unit of claim 10, wherein the second heat exchanger assembly includes a radiator that reduces the temperature of coolant in engine.
 16. The air compressor unit of claim 10, wherein baffled louvers are disposed within the rear aperture and mid aperture. 